Dipper door control



P. BURKE 2,016,032

DIFPER DOOR CONTROL @ct. I, 1935.

Filed Nov. 11, 1933 INVENTOR LJIII ATTORNEY I BY 75% am Patented Oct. 1, 1935 UNITED STATES PATENT OFFICE DIPPER DOOR CONTROL Application November 11, 1933, Serial No. 697,571

5 Claims.

The invention relates toshovels and more particularly to a control for the dipper door thereof.

In power shovels, the door is secured to the dipper by suitable latch mechanism to close it while the dipper is receiving or carrying its load and is allowed to swing free during the discharge of the load. Frequently the dipper door is rapidly opened and shut as in the shaking of the dipper during discharge operations. In such operations the door, which is allowed to swing freely on its outward stroke, usually has its outward movement limited by striking some unyielding part of the shovel structure and repeated contact of this sort results in damage to the parts and eventual depreciation and breakage. The object of the present invention is to provide a simple and efiicient construction for limiting the outward swinging movement of the door and cushioning such movement and more particularly to provide a leaf spring or springs for this purpose mounted and arranged in a novel manner. The leaf spring construction has the advantage of providing interleaf friction which the door must overcome in coming to rest. This friction dissipates an appreciable portion of the kinetic energy of the moving door, thus removing part of the demand for elasticity on the part of the spring. Furthermore, with the leaf spring construction, the advantages of a spring having a variable effective length may be readily obtained.

The invention further consists in the several features hereinafter set forth and more particularly defined by claims at the conclusion hereof.

In the drawing;

Fig. 1 is a side elevation view of a device embodying the invention, parts being broken away and parts being shown in section;

Fig. 2 is a detail sectional view taken on the line 2--2 of Fig. 1 and showing the door as it nears the end of its outward movement;

Fig. 3 is a sectional view similar to Fig. 2 showing the door at the end of its outward movement;

Fig. 4 is a side elevation view of a modified form of dipper door control.

Referring to the drawing, the numeral 5 designates a dipper stick which, as is well known in power shovels, is supported upon a swinging boom so that it may reciprocate lengthwise and swing relative thereto, said stick having a dipper 6 of any suitable construction mounted on the outer end thereof.

The dipper 6 has the usual digging teeth 1 and a (1001 3 p voted at a d closing off the back end of the dipper during digging. The door 8 is held shut. by any suitable latch mechanism (not shown) which on being released allows the door 8 to swing freely outwardly.

During the excavating operations it frequently 5 happens that the door 8 is allowed to open with considerable violence, such as when shaking the dipper, and repeated contact of this sort by the door against the usual relatively unyielding part of the shovel structure results in damage to the 10 parts and eventual depreciation and breakage. To prevent such damage I have provided a leaf spring construction adapted to be engaged by a part of the door structure as the door nears the end of. its outward movement to limit and cushion 15 the movement of said door.

Referring to Figs. 1 to 3 inclusive the dipper stick 5 is shown of the two part type and a metal block In is mounted between its parts adjacent the Clipper and has a laminated leaf spring I I clamped 20 thereto intermediate its ends by a clip l2 and bolts l3. This block has recessed end portions M in which the ends of the spring laminations are guided and a convexly curved back I5 for limiting the ultimate flexure of said laminations. 25

The door 8 has a metal block I 6 mounted thereon having spaced abutments I! which, as the door is opened outwardly, respectively engage the ends of the laminated leaf spring II, as shown in Fig. 2, which thereupon yieldingly resist such 30 outward movement, the fiexure of the spring sections being progressively limited, as shown in Fig. 3, by the curved back l5 of the spring supporting block In. Thus the laminated leaf spring ll serves to yieldingly check the outward move- 35 ment of the door and the friction between the laminations of the spring dissipates an appreciable portion of the kinetic energy of the moving door, thus removing part of the demand for elasticity on the part of the spring.

In the modified arrangement shown in Fig. 4 the hinge part 18 of the door has a lug l9 which on the outward swinging movement of the door moves into engagement with the free end of a laminated leaf spring 20 here shown as an- 45 chored at its other end by a bolt 2| to a lug 22 formed as part of the dipper. As the spring 20 is deflected by the force imparted to it by the door, it comes in contact with a fixed abutment or stop 23 and upon further deflection it comes 50 in contact with the abutment 24, after which there is substantially solid contact, the abutments 23 and 24 being shown as a part of the dipper.

Thus in both of the forms of the invention, progressive deflection is met by increasing spring resistance because the effective length of the spring becomes progressively shorter as the deflection increases. Thus a severe opening of the door is met by correspondingly more severe resistance to further opening.

While only a single spring structure is shown in Fig. 4 it will be apparent that a similar structure may be associated with the other hinge of the door if desired.

It is also to be understood that this invention is not to be limited to any particular form or arrangement of parts except in so far as such limitations are included in the appended claims.

What I claim as my invention is: v

1. In a shovel, the combination of a dipper having a swinging door, a laminated leaf spring disposed in the path of outward movement of a part of said door and yieldingly limiting said outward movement, and means for progressively changing the deflection of said spring to effect a rate of increase of deflection less than the rate of increase due to load.

2. In a shovel, the combination of a dipper having a swinging door, a laminated leaf spring, means for anchoring said spring intermediate its ends in the path of outward movement of the door, said door having spaced abutments engageable with the ends of said spring.

3. In a shovel, the combination of a dipper having a swinging door, a laminated leaf spring, means for anchoring said spring intermediate its ends in the path of outward movement of the door, said door having spaced abutments engageable with the ends of said spring, as it nears the end of its outward movement, and means for progressively increasing the resistance of the ends of said spring as their deflection increases.

4; In a shovel, the combination of a dipper having a swinging door provided with a hinge having an abutment, a laminated leaf spring anchored at one end and having its free end disposed in the path of outward swinging movement of said abutment, and spaced stops adjacent said spring for progressively limiting its deflection under the forces imparted to it by the outwardly swinging door.

5. In a shovel, the combination of a dipper having a'swing'ing door, a laminated leaf spring disposed in the path of outward movement of a part of said door and yieldingly limiting the outward movement of said door, and stop means progressively limiting the deflection of said spring with the increase in load thereon.

PAIJL BURKE. 

